Tooling for use with a press brake commonly includes a horizontally elongated punch having a downwardly-facing tip, and a horizontally elongated die having an upwardly open workpiece-contact portion adapted to receive the punch tip during, for example, a workpiece bending operation.
Due to the substantial forces involved in bending operations, it is important that punches and dies be kept in alignment to avoid undue wear, to assure accurate bending, and to avoid breakage. Commonly, the punch is mounted in a fixed position, and the die can be positionally adjusted into precise alignment with the punch tip. When the die holder is then locked in position, relative lateral movement between the punch and die is restrained.
A press brake die commonly has a downwardly extending tang that is mounted in an upwardly open channel of a die holder. Set screws, inserted through the side of the die holder, may be employed to lock the die's tang in the channel. In other cases, the fit between the tang and die holder is sufficiently close that no locking is provided, and as a result, the die can be removed from the die holder with some ease.
Particularly in the latter case (in which the die's tang is simply received in a closely sized channel of the die holder), some slight back and forth rocking motion or “wobble” of the die within the holder can occur, and is difficult to avoid. A very small amount of wobble or play between the die's tang and the channel is magnified at the upper portion of the die (where the die meets the punch tip). It is difficult economically to obtain tolerances that prevent such movement. If most of the wobble is to be avoided by extremely close tolerances in machining the tang and channel, the cost of machining may become economically prohibitive. Furthermore, very close tolerances between the tang and die holder make it difficult to insert the tang into the die holder.
It would be desirable to provide a die holder that offers positive die clamping. It would be particularly desirable to provide a die holder that offers positive clamping without requiring adjustment of set screws or other fasteners that require tools. It would also be desirable to provide a die holder that is convertible between a hydraulically-operable state and a manually-operable state. Further, it would be desirable to provide a die holder having one or more die-contact bodies that deliver downward force to the tang of a die during clamping. Finally, it would be desirable to provide a die holder having selected surfaces coated with wear-resistant coating.